Hello everyone welcomes to Master2Teach step-by-step guide in this video
tutorial we are going to learn as a software engineer
how to start a new project what is a use case diagram different elements of the
use case diagram how to draw use case diagram you will also learn what is and
how to write high-level use case description yeah also I will cover
extended use case description including an alternative on it as a bonus in last we
will see the example of use case diagram I will try my best to explain step by
step from the beginning if you haven't subscribed to our channel please click
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imagine that you are working as a software engineer in IT company your
company has done contract with organization to develop software for
them now how do you start the project as a software engineer sure that you are
not going to start from coding as a software engineer you will follow the
system development lifecycle first of all we need the requirement of the
system to start the project the first step is to gather the requirement during
this phase of software development you have to choose the best software
development methodology so that you can work systematically and smoothly
software development methodology will help you to execute track the project
and reduce the risks of project failure the phases of system development
lifecycle are number one initiation number two system concept development
number three planning number four requirement analysis
number five design number six development number seven integration and
testing number eight implementation number nine operation and maintenance
whereas number ten disposition after requirement analysis we moved forward
designing the system before we start the coding most of the students
misunderstood guarding designing word designing in
software engineering is not talking about making wireframe or prototype
designing it's not about the interface design and the color combination
designing means visualizing the internal systems in the diagram it's a blueprint
of the system software design is concerned with deriving the solution
design can be traced to a customer requirement designing is an iterative
process through his requirements are translated into a blueprint for the
software to be developed we start to design with the high level of
abstraction we can start design in structure of view like starting from
context diagram data flow diagram T of T whereas design can be drawn in
object-oriented view in object-oriented view we start designing from use case
diagram explaining all the systems to clients or team member or someone Hills
he is quite difficult the explainer may forget some main
feature of the system while the listener may have lost what he or she is talking
about explainer think that he has explained very well but actually the
listener may not understand it for example if you want to make a new app
and explain it but the listener doesn't understand how they will interact with
the app or what it would do in this type of scenario the use case diagram is very
helpful simply it shows a system or application people are organization or
other that interact with the system basic flow of the system that the system
or application does it's a very high level diagram and typically won't so a
lot of detail but it's a great way to communicate complex ideas in a purely
basis way use cases so the functionality of the system from the users perspective
each used cases name is usually an active verb and or noun phrase the use
case diagram is usually used to kourin system as well as to Manila
proposed system how do you start drawing use case diagram first of all we have to
list out all the use cases and identify the actor we will learn what are the use
cases and who are the actors in funeral after listing out use cases and
identifying the actor prioritize use cases and focus from the top of the list
the above each of the priority use cases starting with writing description car
hits there are four different elements of the use case diagram they are number
one system number two actor number three use cases whereas number four
relationship let's go one by one number one system the project that you
are developing is a system it could be an application software desktop wave or
mobile or website software component business process or any other projects
the system is representing a rectangle shape where the system name is written
inside the top of the system the rectangle shape helps to define the
overall scope of the system that you are going to develop so that everything that
the system dots up places inside the system whereas anything outside the
rectangle doesn't happen in the system number to actor the actor is
representing by the humanistic a image anyone who used to perform a certain
function in the system is actor actors maybe someone or something that can be a
person and organization another system may seem or any external device so who
or what is going to use our system is actor like costumer stop had mean buying
student/teacher etcetera actor can be categorized in two types number one is
primary actor whereas number two is secondary actor our primary actor
initiate the of the system while the secondary actor
is more reactionary for example customer are the primary actor because the system
is mostly used by the customer whereas buying he is a secondary actor
after all the bank is only going to perform certain functions once the
primary actor does something in other simple world primary actor requests
something's to the system and secondary actors responds to the primary actors
primary actors should be position in the Lipsyte of the system whereas secondary
actor are placed on the right side of the system 3 use kiss all the
functionality that the system does is the use case in an in the world the list
of tasks which the system can perform each use case use case is denoted by the
oval shape for example login check balance transfer pond make a payment
display error message verify login details etc it's good practice to use
the use case in a logical order where possible like in frog logging after that
book service then after that make payment in this way number poor
relationship as we know and after use the system to achieve a goal by
interacting at least one of the use cases within the system for example
customer can log in book service make payments etc so we draw the solid line
between the actor and the use case to show the relationship this type of
relationship is called as an associations and it's just signified a
basic communication or interaction let's go through the type of relationship in
additions to the associations number one include number to extent whereas number
3 generalized
whenever a customer requests our login the system will automatically call the
login verification use case before completing the login process but if the
login detail is incorrect the system will display an error message so Iran
is another extra use case to show the relationship
neither of the actors is directly initiating this verify login display or
message extra use cases they are just immediately going to happen within the
system whenever the actor performs a lock in use case the relationship
between the login use case and the purify login details use case is include
which is written as include because as the login use case is called by the
actor verify login details use case is automatically performed by the system
here login use case is a base use case whereas verify login detail is an
included use case in include relationship whenever the base use case
is in attribution the included use case is auto alt acquitted as well in another
way the base use case requires an included to use case to be complete for
showing include relationship draw - line with an arrow that points to us included
use case and write include as a level another type of relationship is extended
relationship where it's defined the relationship between the base use case
and the extend use case in extend relationship the extend use case may or
may not execute when the base use case is executing the extend use case will
only happen if certain criteria are made in the above example the login is the
page use case whereas the display erode message is extend use case that display
erode message use case main or may not execute when bases case login use case
is executed for the extend relationship between the pace and the extraneous gear
draw the dashed line with an arrow that points towards the base use case and
write extend as level between them another the base example to demonstrate
the different between include an exchange relationship is if he is nice
you will close your eyes that's an include relationship because
it's going to happen whenever we sneeze whereas if you sneeze you might say
excuse me that's an extended relationship because
it supplements the is nice but isn't completely necessary in the staging
process note that include happens every time extent happens just sometimes and
don't forget that the error point in the opposite directions also multiple base
use case can point to the same included or extended use case avoid premature use
overuse and misuse of include and exchange relationship the simpler year
diagram the better when producing a use case model always keep in mind that you
are trying to portray the and for what propose another type of relationship is
generalizer also known as inheritance generalization is showing the
relationship between the parent and the child use case relationship in simple
words generalization is showing the type of actor or use case in the system for
the generalization lesson ship draw slowly line with an arrow from the child
use kissed or actor to parent use case or actor as shown in figure for example
the system may have new customer as well as whole customer which can be shown in
generalization as here another type of notation see is
extension point extension points are just our detailed portion of extended
relationship and also can be shown in the note what sort of conditions would
lead to this extension point in this way you can draw the complete use case
diagram with various elements that helps explain what the system does note that
even complex systems should be restrict or simplicity visualizations or Punk
slanty behavior endless now let's move to that type of use case
description number one high-level use case description number two expanded use
case description number three is essential and number Oh
Israel we are going through the high-level and expanded use case
description high-level use case description is a short non-title
description of each require process in high-level use case description we will
not go through the details on the interactions it's a short non detail
description as shown in below the high-level use case contain use case
where we write the name of the use case that we are going to describe in
high-level this case description number two is actor who is going to call
this use case in description we write or sort non-title this reason another type
of use case description is expanded use case description in expanded use case
description we write the interaction between the actor and the system how the
use case is going to perform in expanded use case description we go through the
interaction between the actor and the system it is the expanded use case
description where we write each steps that takes to happen while executing
that use case for example in role use case in introduced case the actor and
the system is going to crow home like this
in this way we write the each and every step that involves in in the expanded
use case description let's go through the alternative alternative e is nothing
more than the listing out variable the use case can be in for example in line
number five to actor clicks on the children course what if if the client or
customer could not find the suitable course for him or her like we write
alternative courses in line number five the new student doesn't see a suitable
course the use case in also in line number eight it says that pays by credit
card or debit card what if if the user or client does not have card details the
newest friend doesn't have filter David card available the use case in in this
way we list out wherever the use case can be in in the alternative section
I hope you learn from this video tutorial if you have any questions or
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